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Gaidau C, Râpă M, Ionita G, Stanculescu IR, Zaharescu T, Constantinescu RR, Lazea-Stoyanova A, Stanca M. The Influence of Gamma Radiation on Different Gelatin Nanofibers and Gelatins. Gels 2024; 10:226. [PMID: 38667645 PMCID: PMC11049530 DOI: 10.3390/gels10040226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/19/2024] [Accepted: 03/22/2024] [Indexed: 04/28/2024] Open
Abstract
Gelatin nanofibers are known as wound-healing biomaterials due to their high biocompatible, biodegradable, and non-antigenic properties compared to synthetic-polymer-fabricated nanofibers. The influence of gamma radiation doses on the structure of gelatin nanofiber dressings compared to gelatin of their origin is little known, although it is very important for the production of stable bioactive products. Different-origin gelatins were extracted from bovine and donkey hides, rabbit skins, and fish scales and used for fabrication of nanofibers through electrospinning of gelatin solutions in acetic acid. Nanofibers with sizes ranging from 73.50 nm to 230.46 nm were successfully prepared, thus showing the potential of different-origin gelatin by-products valorization as a lower-cost alternative to native collagen. The gelatin nanofibers together with their origin gelatins were treated with 10, 20, and 25 kGy gamma radiation doses and investigated for their structural stability through chemiluminescence and FTIR spectroscopy. Chemiluminescence analysis showed a stable behavior of gelatin nanofibers and gelatins up to 200 °C and increased chemiluminescent emission intensities for nanofibers treated with gamma radiation, at temperatures above 200 °C, compared to irradiated gelatins and non-irradiated nanofibers and gelatins. The electron paramagnetic (EPR) signals of DMPO adduct allowed for the identification of long-life HO● radicals only for bovine and donkey gelatin nanofibers treated with a 20 kGy gamma radiation dose. Microbial contamination with aerobic microorganisms, yeasts, filamentous fungi, Staphylococcus aureus, Escherichia coli, and Candida albicans of gelatin nanofibers treated with 10 kGy gamma radiation was under the limits required for pharmaceutical and topic formulations. Minor shifts of FTIR bands were observed at irradiation, indicating the preservation of secondary structure and stable properties of different-origin gelatin nanofibers.
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Affiliation(s)
- Carmen Gaidau
- Research and Development National Institute for Textiles and Leather-Division Leather and Footwear Research Institute, 93 Ion Minulescu Street, 031215 Bucharest, Romania; (C.G.); (R.-R.C.)
| | - Maria Râpă
- Faculty of Materials Science and Engineering, POLITEHNICA Bucharest National University of Science and Technology, 313 Splaiul Independentei, 060042 Bucharest, Romania;
| | - Gabriela Ionita
- “Ilie Murgulescu” Institute of Physical Chemistry, 202 Splaiul Independentei, 060021 Bucharest, Romania;
| | - Ioana Rodica Stanculescu
- Department of Analytical and Physical Chemistry, University of Bucharest, 4-12 Regina Elisabeta Bd., 030018 Bucharest, Romania;
- Horia Hulubei National Institute of Research and Development for Physics and Nuclear Engineering, 30 Reactorului Str., 077125 Magurele, Romania
| | - Traian Zaharescu
- National Institute for R&D in Electrical Engineering ICPE-CA, 313 Splaiul Unirii, P.O. Box 149, 030138 Bucharest, Romania;
| | - Rodica-Roxana Constantinescu
- Research and Development National Institute for Textiles and Leather-Division Leather and Footwear Research Institute, 93 Ion Minulescu Street, 031215 Bucharest, Romania; (C.G.); (R.-R.C.)
| | - Andrada Lazea-Stoyanova
- National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, 077125 Magurele, Romania;
| | - Maria Stanca
- Research and Development National Institute for Textiles and Leather-Division Leather and Footwear Research Institute, 93 Ion Minulescu Street, 031215 Bucharest, Romania; (C.G.); (R.-R.C.)
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Stanca M, Gaidau C, Zaharescu T, Balan GA, Matei I, Precupas A, Leonties AR, Ionita G. Physico-Chemical Changes Induced by Gamma Irradiation on Some Structural Protein Extracts. Biomolecules 2023; 13:biom13050774. [PMID: 37238645 DOI: 10.3390/biom13050774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/20/2023] [Accepted: 04/28/2023] [Indexed: 05/28/2023] Open
Abstract
In this study, the effect of gamma irradiation (10 kGy) on proteins extracted from animal hide, scales, and wool was evidenced by calorimetric (μDSC) and spectroscopic (IR, circular dichroism, and EPR) methods. Keratin was obtained from sheep wool, collagen and bovine gelatin from bovine hide, and fish gelatin from fish scales. The μDSC experiments evidenced that gamma irradiation influences the thermal stability of these proteins differently. The thermal stability of keratin decreases, while a resistance to thermal denaturation was noticed for collagen and gelatins after gamma irradiation. The analysis of the IR spectra demonstrated that gamma irradiation determines changes in the vibrational modes of the amide groups that are associated with protein denaturation, most meaningfully in the case of keratin. As evidenced by circular dichroism for all proteins considered, exposure to gamma radiation produces changes in the secondary structure that are more significant than those produced by UV irradiation. Riboflavin has different effects on the secondary structure of the investigated proteins, a stabilizing effect for keratin and fish gelatin and a destabilizing effect for bovine gelatin, observed in both irradiated and non-irradiated samples. The EPR spectroscopy evidences the presence, in the gamma-irradiated samples, of free radicals centered on oxygen, and the increase in their EPR signals over time due to the presence of riboflavin.
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Affiliation(s)
- Maria Stanca
- Leather Research Department, Research and Development National Institute for Textiles and Leather-Division Leather and Footwear Research Institute, 93, Ion Minulescu Street, 031215 Bucharest, Romania
| | - Carmen Gaidau
- Leather Research Department, Research and Development National Institute for Textiles and Leather-Division Leather and Footwear Research Institute, 93, Ion Minulescu Street, 031215 Bucharest, Romania
| | | | - George-Alin Balan
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Iulia Matei
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Aurica Precupas
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Anca Ruxandra Leonties
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Gabriela Ionita
- Leather Research Department, Research and Development National Institute for Textiles and Leather-Division Leather and Footwear Research Institute, 93, Ion Minulescu Street, 031215 Bucharest, Romania
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania
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Joly JP, Aricov L, Balan GA, Popescu EI, Mocanu S, Leonties AR, Matei I, Marque SRA, Ionita G. Formation of Alginate/Chitosan Interpenetrated Networks Revealed by EPR Spectroscopy. Gels 2023; 9:gels9030231. [PMID: 36975680 PMCID: PMC10048464 DOI: 10.3390/gels9030231] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 03/17/2023] Open
Abstract
This study analyzes the physico-chemical properties of interpenetrated polymer networks (IPNs) and semi-IPN resulting from cross-linking chitosan with glutaraldehyde and alginate with Ca2+ cations, as a function of the order in which the cross-linking agents are added to the polymer mixture. Three physico-chemical methods were used to assess the differences between systems: rheology, IR spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy. While rheology and IR spectroscopy are commonly used to characterize gel materials, EPR spectroscopy is rarely used, but has the advantage of providing local information about the dynamics of a system. The rheological parameters, which describe the global behavior of the samples, show that semi-IPN systems have a weaker gel behavior and the order of introducing the cross-linker in the polymer systems plays a role. The IR spectra of samples resulting by adding only Ca2+ or Ca2+ as the first cross-linker are similar to that of the alginate gel, while the spectra of samples in which glutaraldehyde is firstly added resemble the chitosan gel spectrum. Using spin-labeled alginate and spin-labeled chitosan, we monitored the changes occurring in the dynamic of the spin labels due to the formation of IPN and semi-IPN. The results show that the order of adding the cross-linking agents influences the dynamic of the IPN network, and that the formation of the alginate network determines the characteristics of the entire IPN system. The EPR data were correlated with the rheological parameters and IR spectra of the analyzed samples.
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Affiliation(s)
- Jean-Patrick Joly
- Aix Marseille University, CNRS, Institut de Chimie Radicalaire, UMR 7273, Case 551, Avenue Escadrille Normandie-Niemen, CEDEX 20, 13397 Marseille, France
| | - Ludmila Aricov
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania
- Correspondence: (L.A.); or (G.I.)
| | - George-Alin Balan
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Elena Irina Popescu
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Sorin Mocanu
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Anca Ruxandra Leonties
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Iulia Matei
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Sylvain R. A. Marque
- Aix Marseille University, CNRS, Institut de Chimie Radicalaire, UMR 7273, Case 551, Avenue Escadrille Normandie-Niemen, CEDEX 20, 13397 Marseille, France
| | - Gabriela Ionita
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania
- Correspondence: (L.A.); or (G.I.)
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Bala D, Matei I, Ionita G, Cosma DV, Rosu MC, Stanca M, Gaidau C, Baleanu M, Virgolici M, Stanculescu I. Luminescence, Paramagnetic, and Electrochemical Properties of Copper Oxides-Decorated TiO 2/Graphene Oxide Nanocomposites. Int J Mol Sci 2022; 23:ijms232314703. [PMID: 36499031 PMCID: PMC9735503 DOI: 10.3390/ijms232314703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022] Open
Abstract
The properties of newly synthesized Cu2O/CuO-decorated TiO2/graphene oxide (GO) nanocomposites (NC) were analyzed aiming to obtain insight into their photocatalytic behavior and their various applications, including water remediation, self-cleaning surfaces, antibacterial materials, and electrochemical sensors. The physico-chemical methods of research were photoluminescence (PL), electron paramagnetic resonance (EPR) spectroscopy, cyclic voltammetry (CV), and differential pulse voltammetry (DPV). The solid samples evidenced an EPR signal that can be attributed to the oxygen-vacancy defects and copper ions in correlation with PL results. Free radicals generated before and after UV-Vis irradiation of powders and aqueous dispersions of Cu2O/CuO-decorated TiO2/GO nanocomposites were studied by EPR spectroscopy using two spin traps, DMPO (5,5-dimethyl-1-pyrroline-N-oxide) and CPH (1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine), to highlight the formation of hydroxyl and superoxide reactive oxygen species, respectively. The electrochemical characterization of the NC modified carbon-paste electrodes (CPE) was carried out by CV and DPV. As such, modified carbon-paste electrodes were prepared by mixing carbon paste with copper oxides-decorated TiO2/GO nanocomposites. We have shown that GO reduces the recombination process in TiO2 by immediate electron transfer from excited TiO2 to GO sheets. The results suggest that differences in the PL, respectively, EPR data and electrochemical behavior, are due to the different copper oxides and GO content, presenting new perspectives of materials functionalization.
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Affiliation(s)
- Daniela Bala
- Physical Chemistry Department, Faculty of Chemistry, University of Bucharest, Regina Elisabeta, No. 4-12, 030018 Bucharest, Romania
| | - Iulia Matei
- “Ilie Murgulescu” Institute of Physical Chemistry, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Gabriela Ionita
- “Ilie Murgulescu” Institute of Physical Chemistry, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Dragos-Viorel Cosma
- National Institute for Research and Development of Isotopic and Molecular Technologies, 67–103 Donat Street, 400293 Cluj-Napoca, Romania
| | - Marcela-Corina Rosu
- National Institute for Research and Development of Isotopic and Molecular Technologies, 67–103 Donat Street, 400293 Cluj-Napoca, Romania
| | - Maria Stanca
- Leather Research Department, National Institute for Textiles and Leather, Division Leather and Footwear Research Institute (ICPI), 93 Ion Minulescu Street, 031215 Bucharest, Romania
| | - Carmen Gaidau
- Leather Research Department, National Institute for Textiles and Leather, Division Leather and Footwear Research Institute (ICPI), 93 Ion Minulescu Street, 031215 Bucharest, Romania
| | - Maria Baleanu
- Horia Hulubei National Institute of Research and Development for Physics and Nuclear Engineering, 30 Reactorului Str., 077125 Magurele, Romania
| | - Marian Virgolici
- Horia Hulubei National Institute of Research and Development for Physics and Nuclear Engineering, 30 Reactorului Str., 077125 Magurele, Romania
| | - Ioana Stanculescu
- Physical Chemistry Department, Faculty of Chemistry, University of Bucharest, Regina Elisabeta, No. 4-12, 030018 Bucharest, Romania
- Horia Hulubei National Institute of Research and Development for Physics and Nuclear Engineering, 30 Reactorului Str., 077125 Magurele, Romania
- Correspondence:
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Neculae AVF, Audran G, Bourdillon S, Ionita G, Joly JP, Marque SR, Matei I, Mocanu S. Conformational changes in β-phosphorylated nitroxides – A powerful tool to probe host–guest interactions. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Matei I, Ariciu AM, Popescu EI, Mocanu S, Neculae AVF, Savonea F, Ionita G. Evaluation of the Accessibility of Molecules in Hydrogels Using a Scale of Spin Probes. Gels 2022; 8:gels8070428. [PMID: 35877513 PMCID: PMC9316983 DOI: 10.3390/gels8070428] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/04/2022] [Accepted: 07/07/2022] [Indexed: 12/04/2022] Open
Abstract
In this work, we explored by means of electron paramagnetic resonance (EPR) spectroscopy the accessibility of a series of spin probes, covering a scale of molecular weights in the range of 200–60,000 Da, in a variety of hydrogels: covalent network, ionotropic, interpenetrating polymer network (IPN) and semi-IPN. The covalent gel network consists of polyethylene or polypropylene chains linked via isocyanate groups with cyclodextrin, and the ionotropic gel is generated by alginate in the presence of Ca2+ ions, whereas semi-IPN and IPN gel networks are generated in a solution of alginate and chitosan by adding crosslinking agents, Ca2+ for alginate and glutaraldehyde for chitosan. It was observed that the size of the diffusing species determines the ability of the gel to uptake them. Low molecular weight compounds can diffuse into the gel, but when the size of the probes increases, the gel cannot uptake them. Spin-labelled Pluronic F127 cannot be encapsulated by any covalent gel, whereas spin-labelled albumin can diffuse in alginate gels and in most of the IPN networks. The EPR spectra also evidenced the specific interactions of spin probes inside hydrogels. The results suggest that EPR spectroscopy can be an alternate method to evaluate the mesh size of gel systems and to provide information on local interactions inside gels.
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Affiliation(s)
- Iulia Matei
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania; (I.M.); (E.I.P.); (S.M.); (A.V.F.N.); (F.S.)
| | - Ana-Maria Ariciu
- IPG Health Consulting, King Edward Street, Macclesfield SK19 1AQ, UK;
| | - Elena Irina Popescu
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania; (I.M.); (E.I.P.); (S.M.); (A.V.F.N.); (F.S.)
| | - Sorin Mocanu
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania; (I.M.); (E.I.P.); (S.M.); (A.V.F.N.); (F.S.)
| | - Alexandru Vincentiu Florian Neculae
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania; (I.M.); (E.I.P.); (S.M.); (A.V.F.N.); (F.S.)
| | - Florenta Savonea
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania; (I.M.); (E.I.P.); (S.M.); (A.V.F.N.); (F.S.)
| | - Gabriela Ionita
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania; (I.M.); (E.I.P.); (S.M.); (A.V.F.N.); (F.S.)
- Correspondence: or
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Răducă M, Martins DOTA, Spinu CA, Hillebrand M, Tuna F, Ionita G, Mădălan AM, Lecourt C, Sutter JP, Andruh M. A new nitronyl‐nitroxide ligand for designing binuclear LnIII complexes: syntheses, crystal structures, magnetic and EPR studies. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202200128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Mihai Răducă
- Universitatea din Bucuresti Inorganic chemistry ROMANIA
| | | | | | | | - Floriana Tuna
- University of Manchester Department of Chemistry and Photon Science Institute UNITED KINGDOM
| | - Gabriela Ionita
- Institute of Physical Chemistry Bucarest Spectroscopy ROMANIA
| | | | - Constance Lecourt
- Universite de Touluuse Laboratoire de Chimie de Coordination du CNRS FRANCE
| | - Jean-Pascal Sutter
- Universite de Toulouse Laboratoire de Chimie de Coordination du CNRS FRANCE
| | - Marius Andruh
- Fac. of Chem - Inorg. Chem Lab University of Bucharest Str. Dumbrava Rosie nr. 23 20464 Bucharest ROMANIA
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Spinu CA, Pichon C, Ionita G, Mocanu T, Calancea S, Raduca M, Sutter JP, Hillebrand M, Andruh M. Synthesis, crystal structure, magnetic, spectroscopic, and theoretical investigations of two new nitronyl-nitroxide complexes. J COORD CHEM 2021. [DOI: 10.1080/00958972.2021.1871900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Cristian Andrei Spinu
- Inorganic Chemistry Laboratory, Faculty of Chemistry, University of Bucharest, Bucharest, Romania
| | - Céline Pichon
- Laboratoire de Chimie de Coordination du CNRS (LCC), Université de Toulouse, CNRS, Toulouse, France
| | - Gabriela Ionita
- “Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Bucharest, Romania
| | - Teodora Mocanu
- Inorganic Chemistry Laboratory, Faculty of Chemistry, University of Bucharest, Bucharest, Romania
- “Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Bucharest, Romania
| | - Sergiu Calancea
- Inorganic Chemistry Laboratory, Faculty of Chemistry, University of Bucharest, Bucharest, Romania
- Faculty of Chemistry and Chemical Technology, Moldova State University, Chisinau, Moldova
| | - Mihai Raduca
- Inorganic Chemistry Laboratory, Faculty of Chemistry, University of Bucharest, Bucharest, Romania
| | - Jean-Pascal Sutter
- Laboratoire de Chimie de Coordination du CNRS (LCC), Université de Toulouse, CNRS, Toulouse, France
| | - Mihaela Hillebrand
- Physical Chemistry Department, Faculty of Chemistry, University of Bucharest, Bucharest, Romania
| | - Marius Andruh
- Inorganic Chemistry Laboratory, Faculty of Chemistry, University of Bucharest, Bucharest, Romania
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Popescu EI, Aricov L, Mocanu S, Matei I, Hristea E, Baratoiu R, Leonties A, Petcu C, Alexandrescu E, Ionita G. Subtle influence on alginate gel properties through host–guest interactions between covalently appended cyclodextrin and adamantane units. NEW J CHEM 2021. [DOI: 10.1039/d1nj01278a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Host–guest interactions between functionalized alginate chains modulate the physico-chemical properties of alginate gels.
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Affiliation(s)
- Elena Irina Popescu
- Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
| | - Ludmila Aricov
- Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
| | - Sorin Mocanu
- Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
| | - Iulia Matei
- Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
| | - Elena Hristea
- Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
| | - Rodica Baratoiu
- Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
| | - Anca Leonties
- Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
| | - Cristian Petcu
- National Institute for Research & Development in Chemistry and Petrochemistry – ICECHIM Bucharest
- Bucharest 060021
- Romania
| | - Elvira Alexandrescu
- National Institute for Research & Development in Chemistry and Petrochemistry – ICECHIM Bucharest
- Bucharest 060021
- Romania
| | - Gabriela Ionita
- Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
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Mocanu S, Ionita G, Matei I. Solvatochromic characteristics of dansyl molecular probes bearing alkyl diamine chains. Spectrochim Acta A Mol Biomol Spectrosc 2020; 237:118413. [PMID: 32380433 DOI: 10.1016/j.saa.2020.118413] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/22/2020] [Accepted: 04/24/2020] [Indexed: 06/11/2023]
Abstract
A series of dansyl-based fluorescent probes bearing linear alkyl-1,n-diamine chains of different length (DA1.n, n = 2-8, 10, 12) was characterized in terms of the absorptive and emissive features in solvents of different polarity and hydrogen bond donor/hydrogen bond acceptor character. The probes show solvent-dependent absorption, a feature that is uncommon among dansyl derivatives. The dual emission of DA1.n probes is strong in non-aqueous solvents and is influenced by the chain length and interactions with the solvent. Solvent effects on the spectral parameters were rationalized on the basis of the Kamlet-Taft and Catalán solvatochromic models, in order to quantify the degree of polarity-driven and hydrogen bonding interactions. A comparative discussion of the results predicted by the two models was made. In ground state, the DA1.n probes act as hydrogen bond acceptors. In excited state, hydrogen bonding is less favoured, the solute-solvent interactions being governed by the increasing polarity of the solvent that results in a large bathochromic shift of the emission. A comparison was made with the spectral features previously reported for the corresponding series of bis-dansyl fluorescent probes (2DA1.n).
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Affiliation(s)
- Sorin Mocanu
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, Bucharest 060021, Romania
| | - Gabriela Ionita
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, Bucharest 060021, Romania
| | - Iulia Matei
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, Bucharest 060021, Romania.
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Ionita G, Ciquier G, Fitzpatrick M. Barriers and facilitators to the use of progress-monitoring measures in psychotherapy. ACTA ACUST UNITED AC 2020. [DOI: 10.1037/cap0000205] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ionita G, Mocanu S, Matei I. Conformational preferences of TEMPO type radicals in complexes with cyclodextrins revealed by a combination of EPR spectroscopy, induced circular dichroism and molecular modeling. Phys Chem Chem Phys 2020; 22:12154-12165. [PMID: 32440670 DOI: 10.1039/d0cp01937b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy is the main tool for evidencing the formation of inclusion complexes of cyclodextrins with paramagnetic guests, based on changes in the EPR parameters. In-depth information on complexation can only be obtained by a combination of physico-chemical methods. Herein we report on the interaction of three TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl) type radicals with cyclodextrins by collecting and analysing data provided experimentally by EPR and circular dichroism spectroscopies and theoretically by density functional theory and molecular docking. The study focused on the pH influence on the complexation of three paramagnetic probes with cyclodextrins. The EPR spectra revealed that the type and protonation state of the substituent linked to the TEMPO structure influences the affinity of the paramagnetic group for the cyclodextrin cavity. Neutral radical species favour stronger association with cyclodextrins and inclusion of the nitroxide group into the cavity, especially in the case of 4-carboxy-TEMPO. Induced circular dichroism signals of neutral species varied in sign and intensity as a function of substituent and cyclodextrin type. Density functional theory and molecular docking results supported the experimental data regarding the conformational preferences of TEMPO radicals in complexes with cyclodextrins.
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Affiliation(s)
- Gabriela Ionita
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, Bucharest 060021, Romania.
| | - Sorin Mocanu
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, Bucharest 060021, Romania.
| | - Iulia Matei
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, Bucharest 060021, Romania.
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Buta MC, Toader AM, Frecus B, Oprea CI, Cimpoesu F, Ionita G. Molecular and Supramolecular Interactions in Systems with Nitroxide-Based Radicals. Int J Mol Sci 2019; 20:ijms20194733. [PMID: 31554219 PMCID: PMC6801970 DOI: 10.3390/ijms20194733] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 09/19/2019] [Accepted: 09/20/2019] [Indexed: 12/25/2022] Open
Abstract
Nitroxide-based radicals, having the advantage of firm chemical stability, are usable as probes in the detection of nanoscale details in the chemical environment of various multi-component systems, based on subtle variations in their electron paramagnetic resonance spectra. We propose a systematic walk through the vast area of problems and inquires that are implied by the rationalization of solvent effects on the spectral parameters, by first-principle methods of structural chemistry. Our approach consists of using state-of-the-art procedures, like Density Functional Theory (DFT), on properly designed systems, kept at the border of idealization and chemical realism. Thus, we investigate the case of real solvent molecules intervening in different configurations between two radical molecules, in comparison with radicals taken in vacuum or having the solvent that is treated by surrogate models, such as polarization continuum approximation. In this work, we selected the dichloromethane as solvent and the prototype radicals abbreviated TEMPO ((2,2,6,6-Tetramethylpiperidin-1-yl) oxyl). In another branch of the work, we check the interaction of radicals with large toroidal molecules, β-cyclodextrin, and cucurbit[6]uril, modeling the interaction energy profile at encapsulation. The drawn synoptic view offers valuable rationales for understanding spectroscopy and energetics of nitroxide radicals in various environments, which are specific to soft chemistry.
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Affiliation(s)
- Maria Cristina Buta
- Institute of Physical Chemistry, Splaiul Independentei 202, 060021 Bucharest, Romania.
| | - Ana Maria Toader
- Institute of Physical Chemistry, Splaiul Independentei 202, 060021 Bucharest, Romania.
| | - Bogdan Frecus
- Institute of Physical Chemistry, Splaiul Independentei 202, 060021 Bucharest, Romania.
| | - Corneliu I Oprea
- Department of Physics, Ovidius University, 900527 Constanţa, Romania.
| | - Fanica Cimpoesu
- Institute of Physical Chemistry, Splaiul Independentei 202, 060021 Bucharest, Romania.
| | - Gabriela Ionita
- Institute of Physical Chemistry, Splaiul Independentei 202, 060021 Bucharest, Romania.
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Abstract
The aim of this study was firstly to determine and quantify the dry eye symptomatology of patients with keratoconus, in comparison with those without this condition and secondly to evaluate the suitability of the spin probe method of electron paramagnetic resonance spectroscopy in analysis of tears secretion. As such were considered two groups of patients for evaluation: 36 cases with keratoconus (keratoconus group) and 36 cases without ocular disease (control group). Besides general ophthalmological examination we have conducted Schirmer test I, tears break-up time (BUT) and quantify the answers about dry eye symptomatology to establish ocular surface disease index (OSDI). We have included a prospective correlation of ophthalmologic parameters with parameters of the spin probes added in tear secretions collected from both groups of patients. The results show that the value of OSDI for patients with keratoconus was higher (41.07 � 23.68) than the corresponding value of the control group (14.63 � 9.27). Also, the patients with keratoconus present lower mean values for BUT and Schirmer tests comparatively with the cases from control group. The electron paramagnetic resonances spectra of the spin probe CAT16 in tear secretions obtained from patients revealed changes that can be related with ophthalmologic parameters.
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Baratoiu R, Mocanu S, Matei I, Bem M, Hristea E, Tecuceanu V, Ionita G. A Comparison of the Behavior of Monomolecular and Dual Molecular Probes in F127/Cyclodextrin Systems. MACROMOL CHEM PHYS 2019. [DOI: 10.1002/macp.201800489] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Rodica Baratoiu
- Romanian Academy; “Ilie Murgulescu” Institute of Physical Chemistry; 202 Splaiul Independentei Bucharest 060021 Romania
| | - Sorin Mocanu
- Romanian Academy; “Ilie Murgulescu” Institute of Physical Chemistry; 202 Splaiul Independentei Bucharest 060021 Romania
| | - Iulia Matei
- Romanian Academy; “Ilie Murgulescu” Institute of Physical Chemistry; 202 Splaiul Independentei Bucharest 060021 Romania
| | - Marioara Bem
- Romanian Academy; “Ilie Murgulescu” Institute of Physical Chemistry; 202 Splaiul Independentei Bucharest 060021 Romania
| | - Elena Hristea
- Romanian Academy; “Ilie Murgulescu” Institute of Physical Chemistry; 202 Splaiul Independentei Bucharest 060021 Romania
| | - Victorita Tecuceanu
- Romanian Academy; “Costin D. Nenitescu” Centre of Organic Chemistry; 202B Splaiul Independentei Bucharest 78100 Romania
| | - Gabriela Ionita
- Romanian Academy; “Ilie Murgulescu” Institute of Physical Chemistry; 202 Splaiul Independentei Bucharest 060021 Romania
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Mocanu S, Matei I, Leonties A, Tecuceanu V, Hanganu A, Minea Z, Stancu A, Popescu EI, Ionita G. New flexible molecular probes bearing dansyl and TEMPO moieties for host–guest interactions in solution and gels. NEW J CHEM 2019. [DOI: 10.1039/c9nj01554j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Host–guest interactions in functionalised alginate gels are evidenced by EPR and fluorescence spectra.
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Affiliation(s)
- Sorin Mocanu
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
| | - Iulia Matei
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
| | - Anca Leonties
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
| | | | - Anamaria Hanganu
- Organic Chemistry Centre of the Romanian Academy
- 78100 Bucharest
- Romania
- Department of Organic Chemistry, Biochemistry and Catalysis
- University of Bucharest
| | - Zamfirica Minea
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
| | - Alina Stancu
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
| | - Elena Irina Popescu
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
| | - Gabriela Ionita
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest 060021
- Romania
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Mocanu S, Matei I, Ionescu S, Tecuceanu V, Marinescu G, Ionita P, Culita D, Leonties A, Ionita G. Complexation of β-cyclodextrin with dual molecular probes bearing fluorescent and paramagnetic moieties linked by short polyether chains. Phys Chem Chem Phys 2018; 19:27839-27847. [PMID: 28990616 DOI: 10.1039/c7cp05276f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Electron paramagnetic resonance (EPR) and fluorescence spectroscopies provide molecular-level insights on the interaction of paramagnetic and fluorescent species with the microenvironment. A series of dual molecular probes bearing fluorescent and paramagnetic moieties linked by flexible short polyether chains have been synthesized. These new molecular probes open the possibility to investigate various multi-component systems such as host-guest systems, polymeric micelles, gels and protein solutions by using EPR and fluorescence spectroscopies concertedly. The EPR and fluorescence spectra of these compounds show that the dependence of the rotational correlation time and fluorescence quantum yield on the chain length of the linker is not linear, due to the flexibility of the polyether linker. The quenching effect of the nitroxide moiety on the fluorescence intensity of the pyrene group varies with the linker length and flexibility. The interaction of these dual molecular probes with β-cyclodextrin, in solution and in polymeric gels, was evaluated and demonstrated by analysis of EPR and fluorescence spectra.
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Affiliation(s)
- S Mocanu
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, Bucharest 060021, Romania.
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Ionita G, Malviya A, Rajbhandari R, Schluter WW, Sharma G, Kakchapati S, Rijal S, Dixit S. Seroprevalence of hepatitis B virus and hepatitis C virus co-infection among people living with HIV/AIDS visiting antiretroviral therapy centres in Nepal: a first nationally representative study. Int J Infect Dis 2017; 60:64-69. [PMID: 28483724 DOI: 10.1016/j.ijid.2017.04.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 04/11/2017] [Accepted: 04/13/2017] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVES To assess the prevalence of human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV) co-infections among people living with HIV (PLHIV) in Nepal. METHODS A sample of 677 PLHIV representing key affected populations (KAP) in Nepal, who were undergoing antiretroviral (ART) therapy in ART clinics around the country, were voluntarily enrolled in the study. Rapid kit-based testing followed by ELISA for validation was performed, focusing on HBV surface antigen (HBsAg) and antibodies against HCV (anti-HCV). A multivariate logistic regression model was used to identify factors associated with HBV and HCV co-infection. RESULTS HCV and HBV co-infection among the 677 PLHIV was found to be 19% (95% confidence interval (CI) 16.6-22.7%) and 4.4% (95% CI 3.1-6.6%), respectively. The Eastern Region had the highest percentage of HCV infection (48%). The age group with the highest rates of co-infection was 30-39 years (58% and 70%, respectively, for HCV and HBV co-infection). After adjusting for confounding, males were more likely to have HBV co-infection than females (adjusted odds ratio (AOR) 4.61, 95% CI 1.42-14.98). Similarly, PLHIV who were male (AOR 5.7, 95% CI 2.06-15.98), had a secondary level of education (AOR 3.04, 95% CI 1.06-8.70), or who were drug users (AOR 28.7, 95% CI 14.9-55.22) were significantly more likely to have HCV co-infection. CONCLUSION This first ever national assessment of HIV, HBV, and HCV co-infection performed among PLHIV in Nepal demonstrates that HCV and HBV infections are a health threat to this population and that interventions are required to mitigate the effects of co-infection and to prevent further morbidity and mortality.
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Affiliation(s)
- G Ionita
- United Nations Development Programme, Project Management Unit, Guinea-Bissau
| | | | - R Rajbhandari
- Centre for Molecular Dynamics Nepal, Kathmandu, Nepal
| | - W William Schluter
- World Health Organization - Western Pacific Regional Office (WPRO), Manila, Philippines
| | | | - S Kakchapati
- Centre for Molecular Dynamics Nepal, Kathmandu, Nepal
| | - S Rijal
- United Nations Children's Fund, Kathmandu, Nepal
| | - S Dixit
- Centre for Molecular Dynamics Nepal, Kathmandu, Nepal
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Carp O, Tirsoaga A, Ene R, Ianculescu A, Negrea RF, Chesler P, Ionita G, Birjega R. Facile, high yield ultrasound mediated protocol for ZnO hierarchical structures synthesis: Formation mechanism, optical and photocatalytic properties. Ultrason Sonochem 2017; 36:326-335. [PMID: 28069217 DOI: 10.1016/j.ultsonch.2016.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 11/28/2016] [Accepted: 12/05/2016] [Indexed: 06/06/2023]
Abstract
Hierarchical flowers-like zinc oxide structures have been successfully obtained by a simple and fast ultrasound-assisted method performed in a ordinary ultrasonic bath using an ammonia solution and zinc acetate, in the absence of any surfactant or template. The composition, structure, crystallinity, morphology and optical properties of the materials obtained at different ultrasound irradiation times were characterized by infrared, UV-Vis and photoluminescence spectroscopy, X-ray diffraction, scanning and transmission electron microscopy investigations. It was proved that the ultrasound irradiation time manipulates both the defect content (implicit the photoluminescent properties) and morphology of the ZnO materials: shorter irradiation times leads to the synthesis of high-defected ZnO structures of flower morphology with triangular-shaped petals, while higher irradiation times favours the formation of low-defected ZnO structures with tipped rod-like petals. A plausible growth mechanism of the architectures that implies aggregation via oriented attachment followed by an Ostwald ripening is advanced based on these results. The ZnO flower-like structures present high photocatalytic activities, a total phenol mineralization being registered in the case of visible light experiments. Electron-spin resonance measurements demonstrate the generation of reactive oxygen species, namely hydroxyl radicals but also C centred radicals adducts derived most probable from the residual acetate adsorbed on ZnO surface.
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Affiliation(s)
- Oana Carp
- "Ilie Murgulescu" Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 060021 Bucharest, Romania.
| | - Alina Tirsoaga
- University of Bucharest, Physical Chemistry Department, Bd. Elisabeta 4-12, 030018 Bucharest, Romania
| | - Ramona Ene
- "Ilie Murgulescu" Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 060021 Bucharest, Romania
| | - Adelina Ianculescu
- "Politechnica" University of Bucharest, Gh. Polizu Street no. 1-7, 011061 Bucharest, Romania
| | - Raluca F Negrea
- National Institute for Materials Physics, Atomistilor Street no. 105 bis, P.O. Box Mg-7, Bucharest-Magurele R-077125, Romania
| | - Paul Chesler
- "Ilie Murgulescu" Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 060021 Bucharest, Romania
| | - Gabriela Ionita
- "Ilie Murgulescu" Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 060021 Bucharest, Romania
| | - Ruxandra Birjega
- National Institute for Lasers, Plasma and Radiation Physics, P.O. Box Mg-27, Bucharest-Magurele, Romania
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Rosanvallon S, Bekris N, Braet J, Coad P, Counsell G, Cristescu I, Grisolia C, Guern FL, Ionita G, Likonen J, Perevezenstev A, Piazza G, Poletiko C, Rubel M, Weulersse JM, Williams J. Tritium Related Studies Within the JET Fusion Technology Work Programme. Fusion Science and Technology 2017. [DOI: 10.13182/fst05-a925] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- S. Rosanvallon
- EFDA Close Support Unit, Culham Science Centre, Abingdon OX14 3DB, U.K. e-mail:
| | - N. Bekris
- Association Euratom/Forschungszentrum Karlsruhe, Postfach 3640, 76021 Karlsruhe, Germany
| | - J. Braet
- Association Euratom/SCK-CEN, Boeretang 200, 2400 Mol, Belgium
| | - P. Coad
- Association Euratom/UKAEA, Culham Science Centre, Abingdon OX14 3DB, U.K
| | - G. Counsell
- Association Euratom/UKAEA, Culham Science Centre, Abingdon OX14 3DB, U.K
| | - I. Cristescu
- Association Euratom/Forschungszentrum Karlsruhe, Postfach 3640, 76021 Karlsruhe, Germany
| | - C. Grisolia
- Association Euratom/CEA, Centre de Cadarache, F-13108 Saint Paul Lez Durance, France
| | - F. Le Guern
- EFDA Close Support Unit, Culham Science Centre, Abingdon OX14 3DB, U.K. e-mail:
| | - G. Ionita
- National Institute for Cryogenics and Isotopic Separation Rm-Valcea, P.O. 4, Box 10, Romania
| | - J. Likonen
- Association Euratom/TEKES, VTT Processes, P.O. Box 1608, FIN-02044 VTT, Finland
| | - A. Perevezenstev
- Association Euratom/UKAEA, Culham Science Centre, Abingdon OX14 3DB, U.K
| | - G. Piazza
- EFDA Close Support Unit, Culham Science Centre, Abingdon OX14 3DB, U.K. e-mail:
| | - C. Poletiko
- Association Euratom/CEA, Centre de Cadarache, F-13108 Saint Paul Lez Durance, France
| | - M. Rubel
- Alfven Laboratory, Royal Institute of Technology, Teknikringen 31, 100 44 Stockholm, Sweden
| | - J. M. Weulersse
- Association Euratom/CEA, Centre de Saclay DPC/SCP, 91191 GIF Cedex, France
| | - J. Williams
- Association Euratom/UKAEA, Culham Science Centre, Abingdon OX14 3DB, U.K
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Ross DF, Ionita G, Stirman SW. System-Wide Implementation of Routine Outcome Monitoring and Measurement Feedback System in a National Network of Operational Stress Injury Clinics. Adm Policy Ment Health 2016; 43:927-944. [DOI: 10.1007/s10488-016-0749-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Neacsu MV, Matei I, Micutz M, Staicu T, Precupas A, Popa VT, Salifoglou A, Ionita G. Interaction between Albumin and Pluronic F127 Block Copolymer Revealed by Global and Local Physicochemical Profiling. J Phys Chem B 2016; 120:4258-67. [DOI: 10.1021/acs.jpcb.6b02199] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Maria Victoria Neacsu
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul
Independentei, Bucharest 060021, Romania
| | - Iulia Matei
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul
Independentei, Bucharest 060021, Romania
| | - Marin Micutz
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul
Independentei, Bucharest 060021, Romania
- Department
of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bd. Regina Elisabeta 4-12, Bucharest 030018, Romania
| | - Teodora Staicu
- Department
of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bd. Regina Elisabeta 4-12, Bucharest 030018, Romania
| | - Aurica Precupas
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul
Independentei, Bucharest 060021, Romania
| | - Vlad Tudor Popa
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul
Independentei, Bucharest 060021, Romania
| | - Athanasios Salifoglou
- Department
of Chemical Engineering, Laboratory of Inorganic Chemistry and Chemistry
of Advanced Materials, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Gabriela Ionita
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul
Independentei, Bucharest 060021, Romania
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Ionita G, Madalan AM, Ariciu AM, Medvedovici A, Ionita P. Synthesis of novel TEMPO stable free (poly)radical derivatives and their host–guest interaction with cucurbit[6]uril. NEW J CHEM 2016. [DOI: 10.1039/c5nj01518a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The line shape analysis of the ESR spectra of TEMPO derivatives in the absence and in the presence of cucurbit[6]uril provides information on host–guest complexes.
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Affiliation(s)
- Gabriela Ionita
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest
- Romania
| | - Augustin M. Madalan
- Inorganic Chemistry Department
- Faculty of Chemistry
- University of Bucharest
- 020464-Bucharest
- Romania
| | - Ana Maria Ariciu
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest
- Romania
- Department of Organic Chemistry
- Biochemistry and Catalysis
| | - Andrei Medvedovici
- Department of Analytical Chemistry
- University of Bucharest
- Bucharest
- Romania
| | - Petre Ionita
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy
- Bucharest
- Romania
- Department of Organic Chemistry
- Biochemistry and Catalysis
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Ionita G, Ariciu AM, Smith DK, Chechik V. Ion exchange in alginate gels--dynamic behaviour revealed by electron paramagnetic resonance. Soft Matter 2015; 11:8968-8974. [PMID: 26399427 DOI: 10.1039/c5sm02062j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The formation of alginate gel from low molecular weight alginate and very low molecular weight alginate in the presence of divalent cations was investigated using Electron Paramagnetic Resonance (EPR) spectroscopy. The transition from sol to gel in the presence of divalent cations was monitored by the changes in the dynamics of spin labelled alginate. The immobilisation of the spin labelled alginate in the gel reflects the strength of interaction between the cation and alginate chain. Diffusion experiments showed that both the cation and alginate polyanion in the gel fibres can exchange with molecules in solution. In particular, we showed that dissolved alginate polyanions can replace alginates in the gel fibres, which can hence diffuse through the bulk of the gel. This illustrates the surprisingly highly dynamic nature of these gels and opens up the possibility of preparing multicomponent alginate gels via polyanion exchange process.
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Affiliation(s)
- Gabriela Ionita
- Romanian Academy, Institute of Physical Chemistry "Ilie Murgulescu", 202 Splaiul Independentei, Bucharest, 060021, Romania.
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Ionita G, Fitzpatrick M, Tomaro J, Chen VV, Overington L. Challenges of using progress monitoring measures: Insights from practicing clinicians. J Couns Psychol 2015; 63:173-182. [PMID: 26651210 DOI: 10.1037/cou0000122] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although integrating progress monitoring (PM) measures into psychotherapy practice can provide numerous benefits, including improved client outcomes, relatively few clinicians use these measures (e.g., Ionita & Fitzpatrick, 2014). To better understand the reasons for clinicians' reluctance, consensual qualitative research methodology was used to examine the challenges faced by clinicians currently using PM measures. Open-ended, semistructured interviews, with 25 clinicians who chose to use PM measures, revealed that clinicians tended to face challenges involving technical concerns, negative responses from others, and personal barriers such as anxiety. The majority of participants discussed ways to overcome the challenges they experienced, including ensuring the fit of the PM measure, explaining measures to others to help engender a positive response, adapting their own perspective, and increasing their own and others' knowledge of the measures. Implications for practicing psychologists and for knowledge translation efforts are discussed.
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Affiliation(s)
- Gabriela Ionita
- Department of Educational and Counselling Psychology, McGill University
| | | | - Jann Tomaro
- Department of Educational and Counselling Psychology, McGill University
| | - Vivian V Chen
- Department of Educational and Counselling Psychology, McGill University
| | - Louise Overington
- Department of Educational and Counselling Psychology, McGill University
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Ionita P, Dinoiu V, Munteanu C, Turcu IM, Tecuceanu V, Zaharescu T, Oprea E, Ilie C, Anghel D, Ionita G. Antioxidant activity of rosemary extracts in solution and embedded in polymeric systems. Chemical Papers 2015. [DOI: 10.1515/chempap-2015-0024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractThe rosemary extract was encapsulated in polyethylene or in covalently-based network gels. The covalent gels were obtained by the reaction of isocyanate end-capped polyethylene glycol (PEG) with β-cyclodextrin or glycerol. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to evaluate the antioxidant activity (AA) of rosemary extract entrapped in polymeric structures and in ethanol or water solutions. The AA of the rosemary extract was determined using a DPPH radical for samples prepared in ethanol, and a water-soluble derivative, the sulphonated DPPH radical (DPPH-SO3Na), for the rosemary extract in water. Formulation of the rosemary extract in polymeric gels ensures a rapid release which determines the AA values similar to those in solution.
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Matei I, Ariciu AM, Neacsu MV, Collauto A, Salifoglou A, Ionita G. Cationic Spin Probe Reporting on Thermal Denaturation and Complexation–Decomplexation of BSA with SDS. Potential Applications in Protein Purification Processes. J Phys Chem B 2014; 118:11238-52. [DOI: 10.1021/jp5071055] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Iulia Matei
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul
Independentei, Bucharest 060021, Romania
- Department
of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bd. Regina Elisabeta 4-12, Bucharest, Romania
| | - Ana Maria Ariciu
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul
Independentei, Bucharest 060021, Romania
| | - Maria Victoria Neacsu
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul
Independentei, Bucharest 060021, Romania
| | - Alberto Collauto
- Department
of Chemical Physics, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Athanasios Salifoglou
- Department
Chemical Engineering, Laboratory of Inorganic Chemistry, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Gabriela Ionita
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul
Independentei, Bucharest 060021, Romania
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Ionita G, Ariciu AM, Turcu IM, Chechik V. Properties of polyethylene glycol/cyclodextrin hydrogels revealed by spin probes and spin labelling methods. Soft Matter 2014; 10:1778-1783. [PMID: 24651650 DOI: 10.1039/c3sm52004h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The properties of a gel consisting of a covalent network formed by the reaction of isocyanate end-capped polyethylene glycol (PEG) with β-cyclodextrin, were investigated by EPR spectroscopy. Spin-labelled cyclodextrin was incorporated into the cross-link points of the gel and at the chain ends. The dynamics of the gel fibres as reported by the spin label, was found to be sensitive to the H-bonding ability of the solvent, density of cross-links and temperature. Addition of spin probes (e.g., TEMPO and adamantane-TEMPO) to the unlabelled gel made it possible to characterise the solvent pools in the gel. While TEMPO was uniformly distributed throughout the solvent pools, the adamantane derivative was located at the gel fibre-solvent pool interface; these two probes thus reported on the different locations in the solvent pools. At low temperature, the gels were shown to prevent ice crystallisation in the solvent pools resulting in the formation of supercooled water. Both probes showed that the water froze at ca. 250 K, thus suggesting that the properties of the supercooled water are uniform across the solvent pools.
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Affiliation(s)
- Gabriela Ionita
- Romanian Academy, Institute of Physical Chemistry "Ilie Murgulescu", 202 Splaiul Independentei, Bycharest 060021, Romania.
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Ionita G, Fitzpatrick M. Bringing science to clinical practice: A Canadian survey of psychological practice and usage of progress monitoring measures. ACTA ACUST UNITED AC 2014. [DOI: 10.1037/a0037355] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Micutz M, Matalon E, Staicu T, Angelescu D, Ariciu AM, Rogozea A, Turcu IM, Ionita G. The influence of hydroxy propyl β-cyclodextrin on the micellar to gel transition in F127 solutions investigated at macro and nanoscale levels. NEW J CHEM 2014. [DOI: 10.1039/c4nj00123k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ionita G, Andronescu C, Giester G, Rompel A. Synthesis and structure of mononuclear Cu(II) complexes containing bis(1-methylimidazol-2-yl)ketone ligands. Inorganica Chim Acta 2013. [DOI: 10.1016/j.ica.2013.04.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Ionita G, Marinescu G, Ilie C, Anghel DF, Smith DK, Chechik V. Sorption of metal ions by poly(ethylene glycol)/β-CD hydrogels leads to gel-embedded metal nanoparticles. Langmuir 2013; 29:9173-9178. [PMID: 23782340 DOI: 10.1021/la401541p] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Inorganic nanoparticles can be embedded within gels by selectively preloading them with suitable molecular precursors followed by reduction or another suitable reaction. Here, we exploit the selective sorption properties of cross-linked β-cyclodextrin/poly(ethylene glycol) hydrogels, in analogy with polyurethane foams, to preconcentrate metal salts (HAuCl4 and K2[Co(SCN)4]) and subsequently generate gel-embedded metal nanoparticles (10-50 nm). The nanoparticles are shown to be immobilized within the gel network as a consequence of their large dimensions in comparison to the gel network pore size. We suggest this is a useful approach for the generalized synthesis of hybrid soft-hard nanomaterials.
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Affiliation(s)
- Gabriela Ionita
- Ilie Murgulescu Institute of Physical Chemistry of the Romanian Academy, 202 Spl. Independentei, Bucharest, 060021, Romania
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Rogozea A, Matei I, Turcu IM, Ionita G, Sahini VE, Salifoglou A. EPR and circular dichroism solution studies on the interactions of bovine serum albumin with ionic surfactants and β-cyclodextrin. J Phys Chem B 2012; 116:14245-53. [PMID: 23163315 DOI: 10.1021/jp308650r] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The interactions of bovine serum albumin (BSA) with ionic surfactants (sodium dodecyl sulfate, SDS, and cetyltrimethylammonium bromide, CTAB) and β-cyclodextrin (β-CD) have been investigated by electron paramagnetic resonance (EPR) and circular dichroism measurements. The spin probe selected to report on the interaction of albumin with surfactants and/or β-CD was 4-N,N-dimethyl hexadecyl ammonium-2,2,6,6-tetramethylpiperidine-1-oxyl iodide (CAT16), on account of (a) its balance between electrostatic and hydrophobic character and (b) the ability of BSA to form complexes with various organic molecules. The distribution of the spin probe among different environments in solutions containing only BSA was confirmed by the existence of two components in the EPR spectra: one revealing a restricted mobility of the spin probe, attributed to the protein-spin probe complex, and another one showing free movement, attributed to the spin probe in solution. The presence of surfactants and/or β-CD alters the distribution of CAT16 between various compartments in each system. Formation of protein aggregates as a result of thermal denaturation was evidenced by the appearance of an immobilized component in the EPR spectrum. This component is not present in the EPR spectra of CAT16 in protein/surfactant or protein/cyclodextrin solutions. Circular dichroism spectra of BSA provided information about changes in the secondary structure of the protein induced by the presence of surfactants and/or cyclodextrin in solution. The results demonstrate that β-CD hinders the interaction between the employed surfactants and the protein. The cationic surfactant (CTAB) induces changes in protein conformation at a lower concentration compared to the anionic surfactant (SDS).
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Affiliation(s)
- Adina Rogozea
- Ilie Murgulescu Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, Bucharest 060021, Romania
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Remes C, Paun A, Zarafu I, Tudose M, Caproiu MT, Ionita G, Bleotu C, Matei L, Ionita P. Chemical and biological evaluation of some new antipyrine derivatives with particular properties. Bioorg Chem 2012; 41-42:6-12. [PMID: 22257969 DOI: 10.1016/j.bioorg.2011.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 12/26/2011] [Indexed: 12/01/2022]
Abstract
Starting from 4-amino-antipyrine, six new compounds were synthesized and characterized. The new compounds contain moieties with particular properties, such are ionophore (benzo-15-crown-5), fluorescent (nitrobenzofurazan), stable free radical (nitroxide), or other types of biological active residues, like nitroderivatives, antipyrine or isoniazid residues. They were fully characterized by appropriate means ((1)H and (13)C NMR, IR, UV-Vis, fluorescence, EPR, elemental analysis) and some of their biological properties were evaluated. Hydrophobicity (R(M0), log P), total antioxidant capacity (TAC), and antimicrobial properties are also presented and discussed.
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Affiliation(s)
- C Remes
- University of Bucharest, Department of Chemistry, Biochemistry and Catalysis, 90-92 Panduri, Bucharest 050663, Romania
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Hristea EN, Bem M, Balaban TS, Eichhöfer A, Caproiu MT, Draghici C, Ionita G, Spataru T, Enache C, Maganu M, Beteringhe A, Hillebrand M, Constantinescu T, Balaban AT. Novel 1,1-diphenylhydrazine derivatives of benzofurazan and their dimerization. ARKIVOC 2011. [DOI: 10.3998/ark.5550190.0012.b19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Tudose M, Badea FD, Ionita G, Maganu M, Caproiu MT, Ionita P, Constantinescu T, Balaban AT. N-Alkoxy-3,5-dinitro-4-aminobenzoic acid derivatives with controlled physico-chemical properties. Struct Chem 2010. [DOI: 10.1007/s11224-010-9666-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Balaban AT, Radutiu AC, Baciu I, Caproiu MT, Draghici C, Beteringhe A, Ionita G, Ionita P, Spataru T, Spataru N, Baratoiu RD, Constantinescu T. Wurster aza-crown ethers with N-para-phenylene-phenothiazine or -phenoxazine groups. ARKIVOC 2010. [DOI: 10.3998/ark.5550190.0010.d29] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Baratoiu RD, Mutihac L, Vasilescu M, Voicescu M, Latus A, Ionita G, Beteringhe A, Constantinescu T, Balaban AT. Chemiluminescence of 5-(azo-para-phenylene-N-aza-15-crown-5)-phthalhydrazide. ARKIVOC 2010. [DOI: 10.3998/ark.5550190.0010.d26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Ionita G, Chechik V. Exploring polyethylene glycol/cyclodextrin hydrogels with spin probes and EPR spectroscopy. Chem Commun (Camb) 2010; 46:8255-7. [DOI: 10.1039/c0cc02759f] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ionita G, Florent M, Goldfarb D, Chechik V. Studying Supramolecular Assemblies by ESEEM Spectroscopy: Inclusion Complexes of Cyclodextrins. J Phys Chem B 2009; 113:5781-7. [DOI: 10.1021/jp8099048] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Gabriela Ionita
- Institute of Physical Chemistry, 202 Splaiul Independentei, Bucharest, Romania 060021, Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel 76100, and Department of Chemistry, University of York, York YO10 5DD, United Kingdom
| | - Marc Florent
- Institute of Physical Chemistry, 202 Splaiul Independentei, Bucharest, Romania 060021, Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel 76100, and Department of Chemistry, University of York, York YO10 5DD, United Kingdom
| | - Daniella Goldfarb
- Institute of Physical Chemistry, 202 Splaiul Independentei, Bucharest, Romania 060021, Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel 76100, and Department of Chemistry, University of York, York YO10 5DD, United Kingdom
| | - Victor Chechik
- Institute of Physical Chemistry, 202 Splaiul Independentei, Bucharest, Romania 060021, Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel 76100, and Department of Chemistry, University of York, York YO10 5DD, United Kingdom
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Ionita G, Maganu M, Caproiu MT, Ionita P. Functionalized Hybrid Nanoparticles and their Interaction with Spin-Labeled Cyclodextrin. J Inorg Organomet Polym Mater 2009. [DOI: 10.1007/s10904-009-9260-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Ionita G, Caragheorgheopol A, Caldararu H, Jones L, Chechik V. Inclusion complexes of cyclodextrins with nitroxide-based spin probes in aqueous solutions. Org Biomol Chem 2008; 7:598-602. [PMID: 19156327 DOI: 10.1039/b817290k] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Formation of inclusion complexes between several cyclodextrin derivatives and TEMPO and DOXYL-based spin probes was studied by EPR spectroscopy. Competition between alkyl chains and nitroxide functionalities for cyclodextrin cavities leads to different types of complexation. Long alkyl chains in amphiphilic spin probes interact preferentially with cyclodextrins, and TEMPO units in such molecules are unaffected by complexation. DOXYL-type spin probes however form stronger complexes with cyclodextrins; this complexation changes hyperfine splitting and tumbling rate of the nitroxide group. Comparison of EPR spectra of free cyclodextrin and cyclodextrin-based polymeric nanocapsules made it possible to assess the tumbling of the spin probe inside the cyclodextrin units without the contribution of the tumbling of the whole complex.
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Affiliation(s)
- Gabriela Ionita
- Laboratory of Quantum Chemistry and Molecular Structure, Institute of Physical Chemistry Ilie Murgulescu, Splaiul Independentei 202, Bucharest, 060021, Romania.
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Caproiu MT, Ionita G, Draghici C, Ionita P. Synthesis and characterisation of several di-, tri-, and tetra- radicals linked by flexible or rigid linkers. ARKIVOC 2008. [DOI: 10.3998/ark.5550190.0009.e16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Voicescu M, Ionita G, Beteringhe A, Vasilescu M, Meghea A. The Antioxidative Activity of Riboflavin in the Presence of Antipyrin. Spectroscopic Studies. J Fluoresc 2008; 18:953-9. [DOI: 10.1007/s10895-008-0354-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2007] [Accepted: 02/25/2008] [Indexed: 10/22/2022]
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Abstract
Complexation of beta-cyclodextrin with flexible nitroxide biradicals linked by a polyethylene glycol chain was monitored by EPR spectroscopy. The EPR spectra of the uncomplexed biradicals show an exchange interaction due to the flexibility of the polyethylene glycol chain. Complexation with cyclodextrin leads to the disappearance of the exchange interaction in the EPR spectra. The complexation can be reversed by the addition of competing guests (e.g., adamantane derivatives). At high concentration, the inclusion complexes precipitate, and differential scanning calorimetry (DSC) of the precipitates proved the formation of complexes. Elemental analysis data revealed that the complexes contain several cyclodextrin units per biradical but that the composition was not stoichiometric.
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Affiliation(s)
- Gabriela Ionita
- Laboratory of Quantum Chemistry and Molecular Structure, Institute of Physical Chemistry Ilie Murgulescu, Bucharest, Romania.
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